My 2008 600rr starts and runs fine. When I turn the key on, the gauge cluster "boots up" normally- the tach needle winds up and back down to 0, the speedo scrolls from 150 mph to 0, and all the necessary lights come on. However when I begin riding, the tachometer will correctly indicate engine rpms, but the speedometer does not read any speed, it simply indicates "0 mph." Where do I start to fix a problem like this?

 

After doing a little research, I decided to go at it myself. I located the vehicle-speed sensor on top of the case under the gas tank. I checked for voltage and one of the three wires didn't show any when I tested it. I followed the wire all the way up to where the main harness plugs into the speedo-cluster harness on the right side of the bike behind the side fairing. There, I found that the wire had pulled out of the connector, essentially leaving an open circuit. Plugged it back in and everything works fine. Just giving this solution info in case any runs into a similar problem in the future.